Rock hunters bag five Mars meteorites

(CNN) --Exploring the coldest and hottest places on Earth, space rock hunters have found five new meteorites from Mars, bringing the number of known stones from the red planet to 24.

Planet scientists express keen interest in rare martian meteorites, some of which have offered tantalizing clues about whether the planet once possessed oceans or life.

The recent cache actually includes six specimens, but two are presumed to be chunks from the same meteorite. One of the pair weighs in at 30 pounds (13.7 kg), the second-largest Mars meteorite fragment ever recovered, NASA scientists said this week.

Separate expeditions discovered the rocks in Antarctica and the deserts of Oman and the Sahara, mostly between 2000 and 2001. With little or no dirt, grass or tree cover, deserts and the Antarctic are preferred hunting grounds for space rock collectors.

Bruno Fectay and Carine Bidaut of France bagged one of the most recent finds, known as NWA 1068, in the Western Sahara. The amateur collectors have recovered numerous Mars rocks in the past.

Fectay and Bidaut said scientists even found water from Mars in one of their meteorites.

The pair hire nomads to search the desert for geological souvenirs from space. Mars rocks can fetch up to $3,000 per gram in auctions.

Thin slice of NWA 1068 interior

An estimated 20,000 meteorites strike the Earth every year, but only a handful come from Mars. The most controversial specimen, known as ALH84001, is thought by some to contain fossilized evidence of microbial life.

The identified Mars meteorites are thought to have broken off from the red planet eons ago as the result of sizable comet or asteroid collisions. After floating through space they landed on Earth, one as recently as decades ago.

Papers on the five new martian meteorites will be presented in March at the Lunar and Planetary Science Conference in Texas, according to Ron Baalke of NASA's Jet Propulsion Laboratory. Baalke manages a Web site about Mars meteorites: http://www.jpl.nasa.gov/snc/

Techniques to determine whether meteorites came from Mars include studying their mineral composition and comparing trace gases trapped inside specimens with gases analyzed on the Mars surface by the Viking landers.